Which of the following is NOT one of the four main classes of microorganisms?

The classification of microorganisms typically includes four main classes: bacteria, fungi, viruses, and protozoa. While algae are indeed important organisms in ecosystems, they are not usually categorized as one of the primary classes of microorganisms in the context of infection control and asepsis.

Bacteria are single-celled organisms that can exist in various environments and can cause infections. Fungi include a diverse range of organisms, such as yeasts and molds, some of which can also be pathogenic. Protozoa are single-celled eukaryotic microorganisms that can be responsible for various diseases in humans.

Algae, although they are photosynthetic organisms and can produce oxygen, are typically not included in this direct context, as their role in infection or disease transmission is minimal compared to the other categories. Recognizing this distinction is essential for understanding microbiology and infection control practices.